How much should a two-stroke smoke?

Related:
Create New Tag

1/31/2018 10:03 AM

I have been wondering about this, since I just rebuilt my RM250 and want to get the jetting as clean as I can. Two-strokes on YouTube maintained by amateur mechanics smoke quite a bit. I'm curious of opinions.
I measure leanness/richness by looking at the plug, but wondering how much smoke is too much. When I look at pre-2004 Supercross races, I don't seem to see any smoke at all when the bikes are on the line.

|

It's impossible for a corporation or government to love you or care about you.

1/31/2018 10:06 AM

A properly jetted two-stroke won’t smoke much under load and after it’s warmed up.

They will when cold and warming up, due to the cylinder still being cold and burning off whatever oil or gas was left over from shut down.

|

If you're not mixing gas, you're not haulin ass.

1/31/2018 10:09 AM

not sure about that just make sure it doesn't drink too much

|

"If you are going through HELL, keep going."-Winston Churchill
"A man needs a little madness or else he never dares cut the rope and be free"-Zorba
Blur the technicolor

1/31/2018 10:37 AM

oldblood wrote:

not sure about that just make sure it doesn't drink too much

w00t I did see my RM on the streetcorner, hanging with the wrong crowd.
|

It's impossible for a corporation or government to love you or care about you.

1/31/2018 10:47 AM

My RM250 only smokes for a second after start up. Running 168 main 45 pilot on 3rd clip. 50/50 pump and c12 at 40:1

|

1/31/2018 11:01 AM

Should smoke just enough to engulf the four stroke riders in the pits.

|

1/31/2018 11:41 AM

oldblood wrote:

not sure about that just make sure it doesn't drink too much

NorCal 50+ wrote: w00t I did see my RM on the streetcorner, hanging with the wrong crowd.

LMAO

|

1/31/2018 11:43 AM

None

|

1/31/2018 11:44 AM

How much smoke should a two-stroke smoke if a two-stroke could stroke smoke?

say that 10x fast and there's your answer.

|

1/31/2018 11:50 AM

My vote is none also. If jetted correctly you'll get some when cold and on start up, but once warm it should go away. Also under load when riding there shouldn't be any.

|

2018 KTM 250sx
Instagram CamaroAJ

1/31/2018 11:52 AM

Mine only smokes when it drinks

|

1/31/2018 12:05 PM

I am actually getting ready to ride (hopefully) at altitude up in the Sierra Nevadas, and I put a new FMF gnarly pipe and spark arrestor on it. So seems like a blank slate for jetting.
Running 50/50 VP C-12/pump gas mix with Honda two-stroke at 38:1. I am thinking there will be more low-mid throttle riding on trails so I don't want it running rich and loading up.

|

It's impossible for a corporation or government to love you or care about you.

1/31/2018 12:09 PM

I used to ride a '97 KX250. That motor smoked quite a bit and always had a little oil-drool running down the muffler at the end of the day.

My current '96 CR250 barely smokes at all and there is nothing on the muffler when i'm done riding.

The KX had very nice bottom-end power and I didn't have to revv it much to get me around the track.

The CR needs to be in higher RPM to get to the sweet spot in power.

I've run 40:1 Maxima Super M 100% of the time on both bikes.

In short: I think it depends on the motor and hp/torque curve. Then again, I could have just had a poorly tuned KX.

|

Life's a garden, dig it.

1996 CR250R
2016 YZ450F
2001 Suzuki Bandit 600

1/31/2018 12:13 PM

As mentioned, when warming up it can smoke quite a bit. Once warm you should hardly notice it.

Also, you should be pinning it. Most smoke and spooge problems can be cured by not being a bitch with the throttle. tongue

|

James

1/31/2018 12:17 PM

How much should a two-stroke smoke?

That's a tough question, but the short answer is: A LOT

You see, many of us cherish the old 2 smokers and while some may say, jet it this way - or keep it lean that way: nonsense.

You bought a 2 smoker for a reason. You want that puppy running RICH. Better lubrication for the piston, allows less friction and more horsepower. In addition, you should be making an effort to "smoke out" your competitors.

You think it's an accident once Ronny Mac blasts into the lead during a moto, no one ever passes him back? That's right. SMOKE SCREEN makes it impossible to pass once leading.

Your best bet is to dump 2 bottles of Yamalube into the tank, then top her off at the gas station with Leaded fuel. The mix of leaded and extra oil is Primo.

Good luck, your mileage may vary.

|

1/31/2018 12:45 PM

More oil means leaner in my book. Less fuel more lean.

|

1/31/2018 12:46 PM

mxridr wrote:

How much should a two-stroke smoke?

That's a tough question, but the short answer is: A LOT

You see, many of us cherish the old 2 smokers and while some may say, jet it this way - or keep it lean that way: nonsense.

You bought a 2 smoker for a reason. You want that puppy running RICH. Better lubrication for the piston, allows less friction and more horsepower. In addition, you should be making an effort to "smoke out" your competitors.

You think it's an accident once Ronny Mac blasts into the lead during a moto, no one ever passes him back? That's right. SMOKE SCREEN makes it impossible to pass once leading.

Your best bet is to dump 2 bottles of Yamalube into the tank, then top her off at the gas station with Leaded fuel. The mix of leaded and extra oil is Primo.

Good luck, your mileage may vary.

Nothing like that early morning carpet of smoke through the pits to disorient the competition before practice.
Don't laugh- I have run bikes wayyy too rich in my time. Muffler spooge etc. But I have becoming a jetting snob- that is why I run 38:1. Want it crisp without seizing anything of course. The RM pings or surges anyhow without some race gas, is my experience.

|

It's impossible for a corporation or government to love you or care about you.

1/31/2018 12:59 PM

How much smoke should a two stroke smoke if a two stroke could stroke smoke?

|

Washed up Canadian ex-pro couch racer. Selling bikes for a living

2008 KTM 525XC
2009 KTM 450SX
2016 YFZ450R